Turning Waste Plastic into Parkinson's Drug Using Engineered Bacteria

Researchers at the University of Edinburgh have developed a biological process that converts waste plastic into L-DOPA, a key drug used to treat Parkinson’s disease. By engineering bacteria to transform PET into a valuable pharmaceutical compound, the approach combines recycling with biomanufacturing and highlights new pathways for sustainable use of plastic waste.

Polyethylene terephthalate (PET), widely used in packaging, is typically difficult to recycle efficiently. Now, researchers have demonstrated a process that converts this post-consumer plastic into L-DOPA, a frontline treatment for Parkinson's disease.

The process begins by breaking down PET into terephthalic acid, which is then biologically converted into L-DOPA using engineered E. coli. This marks the first time a biological system has been designed to transform plastic waste into a therapeutic compound for neurological disease.

The innovation lies in combining synthetic biology with chemical recycling. The modified bacteria carry out a sequence of reactions that convert plastic-derived molecules into high-value products.

This approach demonstrates the potential of bio-upcycling, where waste materials are not merely recycled but transformed into products of significantly higher value, including pharmaceuticals, chemicals and materials.

Compared with conventional pharmaceutical production, which often depends on fossil-based feedstocks, this method offers a more resource-efficient and low-emission alternative.

It also addresses key challenges in plastic waste management:

• incomplete recycling rates
• loss of valuable carbon resources
• environmental pollution

By recovering carbon from waste plastic, the process supports the development of a circular economy in the chemical and pharmaceutical industries.

The research team has successfully demonstrated L-DOPA production at preparative scale and is now working on scalability and process optimisation.

The work is part of the Carbon-Loop Sustainable Biomanufacturing Hub, which focuses on converting industrial waste into sustainable chemicals and materials. The goal is to enable industrial-scale applications that combine recycling, biotechnology and manufacturing.

Beyond Parkinson's treatment, the platform could be adapted to produce a range of products, including:

• flavourings and fragrances
• cosmetic ingredients
• industrial chemicals

This highlights the broader role of engineering biology in transforming waste streams into valuable resources.